The moults of captive Scottish ptarmigan (Lagopus mutus)

The moults of captive Scottish ptarmigan were studied at Banchory, north-east Scotland from December 1968 to February 1971. In the autumn moult (June to September) which included the primaries, cock ptarmigan moulted earlier and more completely than hens. In the winter moult (September to February) hens moulted earlier and both sexes moulted more completely than in spring. In the spring moult (February to June) cocks moulted more rapidly to begin with but by mid-April hens had caught up and thereafter moulted at least as rapidly as cocks. When kept indoors at slightly higher temperatures ptarmigan grew more pigmented feathers during the winter moult. In a colder winter the birds became whiter than in a milder one. First-winter ptarmigan completed the winter moult later than older birds. Birds from the Cairnwell hills had more dark feathers in winter than those from the eastern Cairngorms. There was no correlation between the start or finish of egg-laying and moulting.     

Moults of wild Scottish ptarmigan, Lagopus mutus, in relation to sex, climate and status

The three annual moults and plumages of Scottish ptarmigan ( Lagopus mutus ) were studied from shot specimens but particularly from field observations. Cocks were ahead of hens in showing the grey autumn plumage but hens were ahead of cocks in turning white in winter. Although cocks were ahead in growing summer plumage, after late April the hens passed them. Ptarmigan on the same hill turned dark earlier in mild than in cold springs.     

Chick Nutrition and Mortality in Captive Willow Ptarmigan (Lagopus L. Lagopus)

Willow ptarmigan chicks were reared during 8 years on concentrates supplemented with blueberry plants. Mortality during the first 3 weeks after hatching ranged between 33 and 65 %, and was mainly caused by enteritis and digestive tract obstructions. The annual variations in chick survival seemed to be caused by the variations in plant phenology. The survival was highest when spring and blueberry plant development was late, and lowest when spring was early and warm, leading to early lignification of blueberry plant leaves.     

Parental Nutrition and Chick Production in Captive Willow Ptarmigan (Lagopus L. Lagopus)

The breeding performance of captive willow ptarmigan on different diets has been studied. The nutritional factors tested were protein concentration, natural feed supplement and grass meal and flavonoid admixture, and effects on egg numbers, fertility, hatchability, chick weights at hatching and 0–14 days mortality have been recorded. The breeding performance of ptarmigan hen in captivity showed great individual variations. Egg numbers were not statistically different in groups fed the different diets. Hens fed a 15 % crude protein died tended to produce smaller chicks with significantly lower viability than chicks from hens fed a 20 % crude protein diet. Supplement of natural feed tended to increase the number of chicks hatched through a combination of tendency to higher egg numbers and improved fertility. These tendencies were, however, statistically nonsignificant. Inclusion of 34 % grass meal to the diet also tended (non-significantly) to improve fertility and hatchability, while inclusion of flavonoids had no positive effect on reproduction. Eggs from captive hens showed significantly lower fertility, and a tendency to lower hatchability than eggs from wild hens. The former difference was probably caused by the close cage confinements for the captive ptarmigan, while the latter condition probably was due to different start of incubation, most of the eggs from wild hens being started naturally.     

Population genetic structure of rock ptarmigan Lagopus mutus in Northern and Western Europe

Alpine species may be losing habitat because of global warming. Setting management priorities for such species is thus urgent and cannot be achieved without data on population structure. We studied the structure of rock ptarmigan (Lagopus mutus) populations in the Pyrenees, Alps and Norway, using six microsatellites. We found that rock ptarmigan in the Pyrenees were genetically impoverished compared with those in the Alps and Norway, and displayed a greater divergence (Pyrenees vs. Alps or Norway: theta(ST) = 0.16, Alps vs. Norway, theta(ST) = 0.04). In the Alps, despite a weak genetic differentiation between localities up to 200 km apart (theta(ST) = 0.011), a significant isolation-by-distance (IBD) effect was detected. When computed for each sex separately this IBD effect was significant for males but not for females, suggesting that males are highly philopatric.     

Maternal antibodies postpone hantavirus infection and enhance individual breeding success

The transfer of maternal antibodies from mother to progeny is a well-known phenomenon in avian and mammalian species. Optimally, they protect the newborn against the pathogens in the environment. The effect of maternal antibodies on microparasite transmission dynamics may have important consequences for both the fitness of the host and the epizootic processes of the pathogens. However, there is a scarcity of studies examining these effects in free-living wild species. We studied the influence of maternal antibodies against the zoonotic Puumala hantavirus (PUUV) on the fitness of bank voles (Clethrionomys glareolus) and on PUUV transmission by exposing young maternal antibody-positive (MatAb+) and negative (MatAb-) bank voles (n=160) to PUUV in experimental populations. PUUV-specific maternal antibodies delayed the timing of infection. Females were more susceptible to PUUV infection than males. Interestingly, both the females and the males with maternal antibodies matured earlier than the other individuals in the population. Our results highlight the significance of maternal antibodies in the transmission of a pathogen and in the breeding success of the carriers.     

Impact of egg harvesting on breeding success of black-headed gulls,Larus ridibundus

Gull colonies world-wide have been harvested for their eggs for centuries with minimal knowledge of the impacts on breeding. Although most Laridae can replace lost eggs, they have comparatively high energetic demands for egg production. In this paper we assess the impacts of a licensed egg harvest on the breeding success of black-headed gulls Larus ridibundus, which nest colonially in an EU Special Protection Area in Hampshire, southern England. We compared egg volume, hatching and chick survival from harvested and un-harvested nests in central and fringe positions within colonies of various sizes, including colonies with no harvesting activity. Eggs from various laying stages were collected from harvested and un-harvested colonies of similar pre-harvest intrinsic quality, for comparison of their volumes, yolk-to-albumen ratios and eggshell thickness. Egg volume and the yolk-to-albumen ratio depended on laying time and location, with the largest eggs laid during the peak period by birds breeding in central positions on large colonies. Eggs produced by these peak layers also had the largest yolk-to-albumen ratios. Harvested sites were characterised by reductions in egg volume, yolk-to-albumen ratio and eggshell thickness, which translated to poorer hatching success and chick survival. Harvested sites also had a higher proportion of abnormal eggs, particularly taking the forms of small yolkless eggs and unpigmented eggs. The reduced breeding success on harvested colonies is likely to be linked to depletion of the female's endogenous reserves which can also reduce future survival and breeding propensity.     

Age-specific patterns of reproduction in White-tailed and Willow Ptarmigan Lagopus leucurus and L. lagopus

Although many studies report a difference in reproductive success between old and young birds, little is known about how, why and when productivity changes as individuals age. We examined age-dependent reproduction in two bird species that inhabit harsh tundra environments: White-tailed Ptarmigan Lagopus leucurus in alpine areas and Willow Ptarmigan Lagopus lagopus in subarctic Canada. We evaluated reproductive performance in the light of three hypotheses: constraint, restraint and selection. Using cross-sectional and longitudinal data, we observed significant age effects in seven of the eight life history and behavioural traits examined for the two species. However, the pattern of age effects variedconsiderably across life history stages; younger birds generally had smaller clutches, later laying dates and poorer spring body condition, but the nesting success did not vary with age. Brood-rearing and renesting abilities were greater for older parents. The oldest age class of White-tailed Ptarmigan showed reproductive senescence for laying date and clutch size but fledged such a large proportion of the brood that they had the highest overall production of any class. It thus appears that parental experience can compensate for reduced physical ability to produce eggs. Annual mortality rates for breeding females were U-shaped for White-tailed Ptarmigan, with higher rates for young and old birds, but mortality did not change with age in Willow Ptarmigan. Overall, the two species differed in the presence of age dependence for only two traits (renesting ability and annual survival). Age-dependent effects were generally greater for White-tailed Ptarmigan than for Willow Ptarmigan. The patterns of mortality and fecundity we observed in ptarmigan provide general support for the constraint hypothesis of reproductive performance. By examining discrete stages of reproduction, we identified the life history stages where age effects occur and propose proximate mechanisms responsible for these effects.     

Protein utilization during starvation in fat and lean Svalbard ptarmigan (Lagopus mutus hyperboreus)

Summary Body protein sparing during starvation has been examined in fat and lean Svalbard ptarmigan. Protein utilization was determined from daily N excretion and from the rate of decrease in body mass. Changes in plasma concentrations of -hydroxybutyrate, free fatty acids, glucose, and uric acid were also recorded. When fat birds were starved for 15 days protein catabolism initially fell (phase I) and was thereafter kept low (phase II). This was evident from the temporal pattern in both N excretion and body mass loss. In two birds, N excretion eventually increased, revealing enhanced protein catabolism and thus a third phase of starvation. Changes in protein utilization were paralleled by changes in plasma uric acid. Approximately 9% of the energy demand was covered by breakdown of body protein during phase II. The importance of fat catabolism in providing energy was indicated by markedly elevated plasma levels of -hydroxybutyrate and free fatty acids. When lean birds were starved for 5 days there appeared to be no phase II. The temporal pattern of body mass loss indicated phase I and III but that of N excretion only phase III. The relative contribution of body protein to energy demand increased from 22% at day 2 to 41% at the end of starvation and was paralleled by increased plasma uric acid. When data from lean and fat birds were pooled, the changes in uric acid and N excretion were highly correlated (r=0.92, P<0.001), indicating that plasma uric acid is a reliable index of protein breakdown in starving Svalbard ptarmigan. In conclusion, starving fat Svalbard ptarmigan have a much greater capacity to spare body protein than lean birds. Fat birds effectively reduce protein catabolism and maintain this at a low level whereas starving lean birds increase protein catabolism.Abbreviations -OHB -hydroxybutyrate - BM body mass - BMR basal metabolic rate; dne daily nitrogen excretion - FFA free fatty acids - MR metabolic rate     

Golden Plover Pluvialis apricaria breeding success on a moor managed for shooting Red Grouse Lagopus lagopus

Capsule The best estimate of breeding success was a mean of 0.57 fledglings per pair, which when combined with adult survival rates, successfully explained the observed population trend.

Aims To quantify Golden Plover breeding success on a moor managed for shooting Red Grouse Lagopus lagopus.

Methods An intensive study recorded the fate of individual Golden Plover nests and, using radiotelemetry, chicks. The factors associated with mortality were examined, allowing the construction of a model of breeding success. Adult survival was estimated from return rates of colour-ringed birds.

Results Estimated rates of daily nest survival during laying (0.8636) were significantly lower than during incubation (0.9913). The daily survival rate of chicks less than nine days (0.8868) was significantly lower than for older chicks (0.9792). A population model based on these parameters overestimated the rate of nest losses, but accurately described brood survival and fledging success. Although predation rates were low, poor survival of young chicks through starvation or exposure suggest other factors were limiting breeding success at the study site.

Conclusions Predation rates of Golden Plover nests and chicks can be low on moorlands managed for shooting Red Grouse. However, in the absence of predation, other factors may still reduce chick survival and limit breeding success.     

Effect of weather on the reproductive rate of Rock Ptarmigan Lagopus muta in the eastern Pyrenees

Understanding the effects of climate on avian life history traits is essential if we wish to predict the demographic consequences of expected climatic changes. We investigated the influence of weather conditions on the reproductive success of Rock Ptarmigan Lagopus muta in the eastern French Pyrenees, one of the southernmost areas inhabited by the species. Reproductive success was estimated in early August between 1997 and 2006 by counting adults and well-grown chicks with pointing dogs. The number of young per adult varied from 0.08 to 0.72. Using Poisson regression and Akaike's information criterion, we selected the best model explaining the effect of weather (date of snowmelt and, for both laying/incubation and post-hatching periods, mean minimum and maximum temperatures, monthly rainfall and number of days with rain) on the proportion of young in August. Reproductive success was positively associated with early appearance of snow-free ground, and date of snowmelt alone was the model that best explained annual variation in reproductive success. Other models, which included a negative effect of rainfall, particularly after hatching, also had some support. Hence, both pre-laying and post-hatching weather conditions influenced reproductive success of Rock Ptarmigan in the eastern French Pyrenees. On a continental scale, reproductive success of alpine populations of Rock Ptarmigan is consistently lower than that of northern populations. This difference in productivity may be partly correlated with climatic conditions observed along an arctic–alpine gradient, the amount and variation of rainfall being greater in southern alpine areas than elsewhere in the species' range.     

Seasonal and daily variations in plasma melatonin in the high-arctic Svalbard ptarmigan (Lagopus mutus hyperboreus).

This study presents the daily rhythm of melatonin secretion throughout one year in a bird from the northern hemisphere, the Svalbard ptarmigan (Lagopus mutus hyperboreus), which lives naturally at 76-80 degrees N. Eight Svalbard ptarmigan were caged outdoors at 70 degrees N and blood sampled throughout one day each month for 13 months. At this latitude, daylight is continuous between May and August, but there is a short period of civil twilight around noon from late November to mid January. There was no daily rhythm in plasma melatonin in May-July. Plasma melatonin levels varied significantly throughout the day in all other months of the year, with the nighttime increase reflecting the duration of darkness. The highest mean plasma concentration occurred at midnight in March (110.1 +/- 16.5 pg/ml) and represented the annual peak in estimated daily production. Around the winter solstice, melatonin levels were significantly reduced at noon and elevated during the nearly 18 h of consecutive darkness, and the estimated mean daily production of melatonin was significantly reduced. Thus, at the times of the year characterized by light-dark cycles, melatonin may convey information concerning the length of the day and, therefore, progression of season. The nearly undetectable low melatonin secretion in summer and the reduced amplitude and production in midwinter indicate a flexible circadian system that may reflect an important adaptation to life in the Arctic.     

Nephritis and Uric Acid Diathesis in Captive Willow Ptarmigan (Lagopus L. LagØPus)

Mortality due to nephritis and uric acid diathesis was observed during the fall and winter in captive willow ptarmigan. The present study examined how feed protein concentration influences feed and water consumption, plasma uric acid concentration, and mortality due to nephritis and uric acid diathesis in captive wrillow ptarmigan. An increase in feed protein concentration from 14 to 24 % resulted in reduced feed consumption and increased plasma uric acid concentration. Mortality due to nephritis and uric acid diathesis was not influenced by variations in feed protein concentration, but an admixture of 14 % grass meal to the diet reduced the incidence markedly.     

Maternal and interannual comparison of the ovulatory periodicity, egg production and egg quality of the batch-spawning yellowtail flounder

Estimates of the ovulatory periodicity of yellowtail flounder indicate that a 1-day interval, which predominated over all other intervals, may characterize regular ovulation patterns. Females produced a mean number of 14–22 batches in 1994 and 1995, respectively. Batch fecundities usually remained within a range of 10 000–60 000 eggs. Mean egg production increased from 549 756 eggs per female in 1994 to 1 186 881 eggs in 1995. Mean fertilization rates rose interannually from 38 to 57%, while hatching rates, tested in 1994, had a mean of 63%. Maternal variation in egg production and egg quality was large and independent of size differences among females. Some females had disrupted ovulation patterns which affected the realization of potential fecundity contained within the prespawning ovary. High interbatch variation in egg quality was not related to progressive decreases in egg diameter and dry weight over time. Batches with high survival rates appeared at random within a female's duration of ovulation.     

Glacial vicariance and historical biogeography of rock ptarmigan (Lagopus mutus) in the Bering region

In this paper, we address alternative hypotheses for the evolution of subspecies of rock ptarmigan (Lagopus mutus) endemic to the Aleutian Archipelago. To do this we examined patterns of genetic differentiation among populations of rock ptarmigan in the Aleutian Islands and parts of both Alaska and Siberia. Variation in mitochondrial control region sequences of 105 rock ptarmigan from 10 subspecies within the Bering region revealed three major phylogenetic lineages, two of which are endemic to the Aleutian Islands. Accordingly, haplotype and nucleotide diversities of rock ptarmigan within the archipelago are much higher than within mainland Alaska or Siberia. For Aleutian rock ptarmigan, analyses of molecular variance indicated significant genetic structuring and low estimates of gene flow among populations, despite small interisland distances within the archipelago. However, isolation by distance did not describe the pattern of gene flow or differentiation at this scale. Our estimates of divergence times of lineages suggest that Aleutian rock ptarmigan became isolated prior to the most recent Pleistocene glaciation event (late Wisconsin Stade) and that current patterns of genetic variation reflect the postglacial redistribution of divergent lineages and subsequent limited gene flow. In addition, genetic divergence among lineages was concordant with the distribution of plumage types among subspecies. The patterns of genetic variation described here for rock ptarmigan provide evidence for the role of glacial vicariance in contributing to genetic diversity within this and other Bering region species.